Nothing breaks an expense tracker faster than a border. The hotel was in euros, the taxi in lira, half the group prepaid flights in dollars, and now someone's spreadsheet has a column called "roughly USD??". Here's how to handle splitting expenses in different currencieswithout losing your mind — or your friends' money.
Rule 1: log in the currency you paid in
Always record an expense in the currency that actually left someone's pocket. The €80 dinner is €80 — not "$87 give or take." Converting at entry time bakes in a guessed exchange rate forever, and every guess compounds. BillBuddies supports 160+ currencies and lets you set the currency per expense, so the record always matches the receipt.
Rule 2: give the group a home currency
When you create a trip group in BillBuddies, set its currency to the destination — EUR for Europe, THB for Thailand. Most expenses will be local, so most entries need no thought at all. The occasional out-of-currency expense (a dollar-priced tour booked online) can be logged in its own currency.
Rule 3: settle per currency when you can
The cleanest settlement is one that never touches an exchange rate. If the group's balances are mostly in euros, settle in euros — a bank transfer or an in-person cash handoff at the end of the trip. For mixed balances, agree one conversion rate as a group (the mid-market rate on settle-up day works), convert once, and settle the single number. One agreed rate, applied once, is fair to everyone and impossible to argue about later.
The prepaid-flights problem
Common scenario: one organized friend books four flights on their card in USD months before a euro-denominated trip. Don't convert it — log it as a USD expense split four ways in the same group. Their friends owe them a USD amount that stays exact. When settling, either pay that portion in USD or apply the agreed rate at settle-up time.
Why per-group currency beats global conversion
Some apps convert everything into one currency automatically — and charge a subscription for it (this is a Pro feature in Splitwise, as we covered in our Splitwise alternatives comparison). Automatic conversion sounds convenient but hides a real cost: the app picks the rate, the rate moves daily, and the numbers on screen stop matching anyone's receipts. Keeping amounts in their original currency is more honest — everyone can verify every entry against what they actually paid.
A quick pre-trip checklist
- Create the group before departure and set the destination currency.
- Get everyone on the app while you're still on home Wi-Fi.
- Agree upfront: log in paid currency, settle within a week of returning.
- For everything else about running trip finances smoothly, see our group trip expenses guide.
The payoff
Multi-currency trips are exactly where manual tracking collapses and where a proper tool earns its keep. Log every expense in its own currency as it happens, keep the group's home currency sensible, convert once at the end if you must — and the money side of an international trip becomes as boring as it should be.